IP technology is beginning to migrate from the long haul networks into the edge network carriers that are, in-turn, in the early stages of offering a variety of broadband services to business and residential customers. Such broadband services are delivered at the user site via wideband coaxial cable or fiber optic cable, both of which are relatively expensive compared to twisted-pair copper wire and require complex and costly interface equipment to install devices thereto. For small business and home networks, installation costs must be low, with high reliability or predictability of operation, both of which are characteristic of wired systems over short distances. Service providers, because of operational, hardware or time-to-market costs and high capital investments required, are reluctant to make any major changes in their outside plant infrastructure or equipment.
Present high speed data services are provided via the digital subscriber line (DSL) family of technologies such as ADSL, VDSL, HDSL, and IDSL. As is well-known, present DSL services have limited bandwidth and data transfer capabilities and are point-to-point services, i.e., service a single device on a line or channel. The limitation of the point-to-point aspect of these DSL delivery systems is that they do not allow for multiple devices or for the network to be directly connected or interconnected. For example, an ADSL (Asymmetric DSL) link consists of a connection from a DSL Access Multiplexer (DSLAM) located in a telephone company central office to an ADSL modem located in a residence or business. If multiple computers at the location of the end user are to be connected together and to the service provider, then the ADSL modem is tied to an additional network within the user site which provides the link between the computers within the user site and to the ADSL modem. The ADSL modem, in turn, transfers data between the user site and the central office. An illustration of such a prior art network is provided in FIG. 6 described hereinbelow.
Referring now to FIG. 6 there is illustrated a typical example of a prior art local network as might be found in a small business or home-user environment. A local network 670 is typically contained within a building or other structure and is coupled through a demarcation point 682 and outside plant wiring 608 to an ADSL modem 606 in the facilities of an interconnect company 604 which provides access to the Internet 602 or, alternatively, a wide-area network (WAN). From demarcation point 682, the premises wiring 684 is coupled to an ADSL modem 612 which demodulates and converts incoming data signals to the data format used by the illustrative Ethernet system utilized in the local network 670. In the Ethernet system, the modem output may be coupled via 10/100 Mbps Ethernet link 614 to a router 616 and thence via link 618 to an Ethernet hub 620 for distribution to individual terminals 610a, 610b, . . . 610n via links 622 connected to the hub 620. Alternatively, the function of the hub 620 could be achieved using a switch 620, as is well known in the field.
Referring further to FIG. 6, it will also be appreciated that the prior art system shown therein has the disadvantage in that it requires a complete local network 670—i.e., a secondary network coupled to the network provided by the interconnect company 604—in order to link a plurality of devices to a single demarcation 682 of a small business or home-use system as contained in a building. Further, in a typical secondary network such as an Ethernet system, the variety of devices to which it may be connected is limited to computers and peripherals thereto, and perhaps telephone equipment (not shown). Yet another disadvantage is the limitation in data rate of the high speed link connected to the user site to 6 or 8 Mbps, which is not adequate for a digitized NTSC video signal plus required overhead of the high speed link.
It is also characteristic of many of the existing broadband network technologies that they do not operate at data rates required for handling multiple channels of video. For example, it is well known that a single channel of standard NTSC video requires 6 to 8 Mbps, and a single channel of high definition (HDTV) video requires 16 to 20 Mbps, when digitized for transmission on a data link. Moreover, these data rates do not include the IP overhead required for digital transmission which can add significantly to these figures. For example, approximately 100 Mbps capability would be required to provide two channels of digitized HDTV simultaneously, one channel to each of two high definition television receivers. Thus, very high data rates are required for providing multimedia services such as “video on demand” or “video broadcasting” in order to ensure transfer of the data at the required packet data rate. Of the existing technologies, VDSL (Very-high-data-rate DSL) and data cable most nearly approach the bandwidth requirements for this type of service; however, neither VDSL (which is limited to 30 MHz bandwidth) or IP-based data cable configurations provide multi-drop capability. Multi-drop capability is very important when considering low-cost and high volume consumer or business applications. Moreover, the increased cost and complexity of existing high speed data distribution technologies act as a barrier impeding the rapid deployment of broadband services in small business or residential applications.
A further aspect of data networks that must be addressed in any broadband network handling real-time data traffic is the quality of service or QoS requirement. QoS, loosely defined, is another name for the design specifications of a data and/or telecommunications network in terms of traffic densities, call priorities, bit error rate (BER), delay and other parameters. QoS thus provides for configuring the network to handle the anticipated traffic, giving consideration to session duration, data volume, priorities, the number of channels available, network traffic densities at peak times or average times, the allowable number of blocked access attempts, the rate of growth of data traffic, etc. In QoS these considerations are processed to enable the best possible utilization of resources of the network for both real-time and non real-time data traffic in a variety of multimedia classes of services such as voice, audio/video data, interactive data, non-interactive data, etc. Properly applied, QoS is “engineered” into each portion of a network intended to carry real time data traffic. However, in the case of individual users or businesses having a need to implement a small, high-speed local network on its side of the demarcation to the premises, or its side of the curb-side “box,” in an effort to provide real-time data communication in, out and within the network, the risk of incompatible equipment and protocols is high, which may result in poor performance. This problem is especially acute when real-time data, high bandwidth/high data rates and a multiplicity of devices are present on the local network. Engineering QoS in a small local network has heretofor been relatively expensive and additionally required specialized knowledge. What is needed, therefore, is a way to provide a local network within, e.g., one hundred meters (100 m) of the curbside terminal, that provides an economical, simple-to-install and use, network facility having full bandwidth, maximum data rates, has multidrop capability and has engineered QoS built-in to provide management of real-time data traffic.